BIOL 117 Lecture Notes - Lecture 14: Food Chain, Herbivore, Decomposer
28 Apr 2016
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Energy flow and trophic structure: previous lectures have dealt with individuals, populations, species, and communities. Finally, we are at a point where we can talk about ecosystems. Ecosystems are communities plus the abiotic conditions that surround them: ecosystem science is largely concerned with 2 things: energy flow and cycling of matter. We will cover matter cycling in the next lecture: energy flow starts with solar radiation striking a part of earth. Some of it is reflected back into the atmosphere and space. Some is absorbed by organisms, soil, water, etc. , increasing their kinetic energy and raising their temperature. Temperature affects the rate of biochemical reactions within an ecosystem. Some of the incoming sunlight is absorbed by chlorophyll in plants: plants use sunlight energy to convert carbon dioxide and water into carbohydrate, which provides herbivores with a usable form of energy. Herbivores take in these molecules and transform them. The new molecules can then be used by carnivores.
